// SPDX-License-Identifier: GPL-2.0

/*
 * Hyper-V nested virtualization code.
 *
 * Copyright (C) 2018, Microsoft, Inc.
 *
 * Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
 */
#define pr_fmt(fmt)  "Hyper-V: " fmt


#include <linux/types.h>
#include <linux/export.h>
#include <hyperv/hvhdk.h>
#include <asm/mshyperv.h>
#include <asm/tlbflush.h>

#include <asm/trace/hyperv.h>

int hyperv_flush_guest_mapping(u64 as)
{
        struct hv_guest_mapping_flush *flush;
        u64 status;
        unsigned long flags;
        int ret = -ENOTSUPP;

        if (!hv_hypercall_pg)
                goto fault;

        local_irq_save(flags);

        flush = *this_cpu_ptr(hyperv_pcpu_input_arg);

        if (unlikely(!flush)) {
                local_irq_restore(flags);
                goto fault;
        }

        flush->address_space = as;
        flush->flags = 0;

        status = hv_do_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE,
                                 flush, NULL);
        local_irq_restore(flags);

        if (hv_result_success(status))
                ret = 0;

fault:
        trace_hyperv_nested_flush_guest_mapping(as, ret);
        return ret;
}
EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);

int hyperv_fill_flush_guest_mapping_list(
                struct hv_guest_mapping_flush_list *flush,
                u64 start_gfn, u64 pages)
{
        u64 cur = start_gfn;
        u64 additional_pages;
        int gpa_n = 0;

        do {
                /*
                 * If flush requests exceed max flush count, go back to
                 * flush tlbs without range.
                 */
                if (gpa_n >= HV_MAX_FLUSH_REP_COUNT)
                        return -ENOSPC;

                additional_pages = min_t(u64, pages, HV_MAX_FLUSH_PAGES) - 1;

                flush->gpa_list[gpa_n].page.additional_pages = additional_pages;
                flush->gpa_list[gpa_n].page.largepage = false;
                flush->gpa_list[gpa_n].page.basepfn = cur;

                pages -= additional_pages + 1;
                cur += additional_pages + 1;
                gpa_n++;
        } while (pages > 0);

        return gpa_n;
}
EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list);

int hyperv_flush_guest_mapping_range(u64 as,
                hyperv_fill_flush_list_func fill_flush_list_func, void *data)
{
        struct hv_guest_mapping_flush_list *flush;
        u64 status;
        unsigned long flags;
        int ret = -ENOTSUPP;
        int gpa_n = 0;

        if (!hv_hypercall_pg || !fill_flush_list_func)
                goto fault;

        local_irq_save(flags);

        flush = *this_cpu_ptr(hyperv_pcpu_input_arg);

        if (unlikely(!flush)) {
                local_irq_restore(flags);
                goto fault;
        }

        flush->address_space = as;
        flush->flags = 0;

        gpa_n = fill_flush_list_func(flush, data);
        if (gpa_n < 0) {
                local_irq_restore(flags);
                goto fault;
        }

        status = hv_do_rep_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST,
                                     gpa_n, 0, flush, NULL);

        local_irq_restore(flags);

        if (hv_result_success(status))
                ret = 0;
        else
                ret = hv_result(status);
fault:
        trace_hyperv_nested_flush_guest_mapping_range(as, ret);
        return ret;
}
EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping_range);